Twelve new HouseGuests entered the Big Brother house: Scott, Morgan, Shane, Neeley, Shelby, Cornbread, Kryssie, Whitney, Justin, Alex, Monte and Danielle. Jason, from Big Brother 17 was voted into the House by America as the thirteenth HouseGuest over Jozea from Big Brother 18. During introductions, Shelby withheld that she was a law school graduate, while Alex and Morgan were shocked seeing each other in the House. Julie Chen revealed that America would impact the game unlike ever before and explained there would be no Jury of evicted HouseGuests to determine the winner instead the viewing public will vote for the winner. Jason began to notice the facial similarities between Alex and Morgan. Discussions of a possible early alliance between Monte, Shane, Scott and Cornbread occurred in the London bedroom during the first night. During their second day in the House, everyone took part in the first Head of Household competition of the season.

• Head of Household ("The BB Bug"): A strange bottle with a blue liquid was placed in the living room with a note "only one may drink." Shane volunteered to drink it and was soon told by Big Brother that he was infected and had to go to the Diary Room. Upon his return, the HouseGuests were under quarantine in the competition and alarms would blast over the next 24 hours. When the first alarm goes off, Shane must infect another HouseGuest, thus eliminating them from the competition. The next HouseGuest must infect a new HouseGuest at the next alarm and so on. The last HouseGuest standing will be the first Head of Household. Monte became the first Head of Household of the season.

The following day, Julie announced to the HouseGuests instead of nomination ceremonies, there will be safety ceremonies. When instructed, the HoH has to save a variable number of HouseGuests to be safe. The two HouseGuests who are not safe will be the nominees of the week. Monte's first instinct was to go after Jason. After the Safety Ceremony, it was revealed that Jason and Danielle were the first nominees on Day 4. Later on in the night, Big Brother called the HouseGuests to the living room. There Julie informed the HouseGuests the viewers will choose a third nominee to sit beside Danielle and Jason. Cornbread was announced as the third nominee chosen by America on Day 5 then Whitney and Alex were chosen to play in the Power of Veto competition while Shane was chosen to host the competition.

• Power of Veto ("Veto Vault"): Inside the house, there are clues to unlocking a vault that's in the backyard. If a HouseGuest thinks they found the 4-digit code they have to run into line outside and wait for their turn to try to unlock the vault. If they get it wrong the vault will buzz incorrect and if they get it right it will buzz correct unlocking the vault and the power of veto. After one hour everyone will get a clue. Jason unlocked the vault with the code 2449 and won the Power of Veto.

Subsequently on Day 7, Jason used the Veto to save himself, and Monte chose to name Kryssie as the replacement nominee. Big Brother called the HouseGuests to the living room again where Julie explained the third interactive element of the season. She informed the HouseGuests that this season America will not only be nominating but evicting a HouseGuest from the house. The nominee that gets the most votes from America will get an extra eviction vote added onto them. As all votes are private, it will not be revealed who America voted to evict. On Day 8, Cornbread was the first person to be evicted from the House by a vote of 9-1-0 with Alex being the only vote against Danielle.

Shortly after the eviction the HouseGuests were instructed to go to the backyard for the next Head of Household competition. Monte, as outgoing Head of Household, was not eligible to compete.

• Head of Household ("Live by the Sword"): Each HouseGuest had a sword, a crown, and knight with their face on it. When the competition begins everyone has two minutes to get their crown pressed against their knights head with the sword. If they do not achieve this by the two-minute mark, they are eliminated. After the two-minute mark, if the crown falls they are also out. When they reach an hour, they will be forced to hold their sword with one hand. They are also not allowed to hold their sword beyond the handle. The last HouseGuest standing becomes the new Head of Household. After an intense battle, Alex outlasted Neeley and became the new Head of Household.

Two days later, the HouseGuests were informed of America's Care Package, where a HouseGuest would receive a special predetermined power from America. It was then revealed that Kryssie won the Save-A-Friend power, which would allow her to keep one other houseguest of her choice safe for the week. She chose to save Jason.

On Days 11 and 12, two safety ceremonies took place, with Alex ultimately nominating Danielle and Shane, the showmance. Before the Power of Veto competition on Day 13, it was made known that America's Nominee was Monte. Jeff Schroeder from Big Brother 11 and Big Brother 13 then arrived at the house as the Veto Host, where Alex, Monte, Shane, Danielle, Scott and Shelby competed for the Power of Veto.

• Power of Veto ("Veto Fore Sale"): Taking turns, each HouseGuest putted at an oversized golf course, scoring points according to the difficulty of the hole that they scored in. After gaining a certain number of points, they could then redeem different punishments, as well as the Power of Veto at the highest required score of 60. The competition would continue until all six prizes had been redeemed, with the last prize remaining going to the last HouseGuest to redeem a prize. Shane won the Power of Veto, with Shelby winning the punishment of wearing a caddy costume for the week, Danielle winning a punishment of fetching golf balls from the swimming pool at random times throughout the week, Alex winning a handicap for the next Head of Household competition, Scott winning a punishment of having to lie in a sand pit for 24 hours, with the exception of using the bathroom, and Monte was not allowed to play for the next Veto competition.

The next day, Shane decided to use the Power of Veto on himself, and Alex chose Kryssie as the replacement nominee. On Day 15, Monte was evicted from the Big Brother house by a vote of 5-4-0, with America casting the deciding vote to evict.

After the eviction, the HouseGuests headed to the backyard for the next Head of Household competition, where Alex, as outgoing HoH, would not compete.

• Head of Household ("BB Bar Code"): Each HouseGuest was given a chain link, and in rounds of 15 minutes, were to measure many randomly numbered planks, and to win, had to find the longest plank. Each round, each HouseGuest could make only one guess, and if it was wrong, had to sit out of the game until the subsequent round. After three rounds, Scott guessed the correct plank and became the 3rd Head of Household of the season.

The next day, America's Care Package was delivered, with Scott winning the power of choosing the type of Veto to be played for this week. He had the choice of the Diamond Power of Veto, which would allow the holder to veto a nominee and also choose the replacement nominee, the Boomerang Power of Veto, which allows the holder to veto both of the nominees on the block, and the Double Power of Veto, which puts two vetoes up for grabs, meaning that there would be two Power of Veto holders.

During the two Safety Ceremonies, Scott nominated Neeley and Kryssie for eviction with Shane as a backdoor target, and the next day, Danielle was nominated by America for eviction. Later that day, the Power of Veto competition took place, where Scott chose to put the Double Power of Veto up for grabs.

• Power of Veto ("Fitting In"): By random draw, the HouseGuests took turns choosing another HouseGuest to challenge in a puzzle, where four tetrominoes had to be fitted into a 4x4 square. The first HouseGuest to complete the puzzle and press the buzzer would eliminate the other HouseGuest from the competition, and would then go back to the end of the line. As the Double Power of Veto was in play, the competition would continue until two HouseGuests were left, where both would win a Power of Veto. Eventually, Justin and Alex both won the Power of Veto.

On Day 21, Justin chose to use the Power of Veto on Kryssie, and Alex chose not to use her Power of Veto. As Head of Household, Scott chose Shane, his main target, as the replacement nominee. Subsequently on Day 22, at the Live Eviction, the vote was split 4-4-0, including America, who voted for Danielle. As such, Scott as Head of Household, had to cast the tiebreaker vote and chose to evict Shane from the Big Brother house, making Shane the third to be evicted.

After Shane was evicted, the HGs were surprised by Paul Abrahamian from Big Brother 18, who was there to host the next Head of Household competition, in which the HouseGuests went to the backyard to compete in.

• Head of Household ("Perfect ShOTT"): The HGs had to search through a large pit of balls for balls which contained a token, and after collecting these tokens, had to use it to redeem red balls from Paul, which would then be used to roll down a winding board, in attempt to land the ball in a box at the end of the board. As Alex had won the handicap from the Veto for Sale competition, she had to wear a disorientating goggle, which would impair her vision. The first HouseGuest to roll a ball into the box would become the next Head of Household, and if no one could complete it within 1 hour, the game would have gone into a tiebreaker. However, Kryssie managed to roll a ball into the box before the time limit was up, and hence became the next Head of Household.

On Day 23, America's Care Package landed in the backyard, and it was announced that Alex had won the Safety Servant care package, which gave her safety for the week, but she had to wear a maid outfit and had to serve the Head of Household when instructed by Big Brother. As Alex was one of the targets of Kryssie, this threw a wrench in Kryssie's plan, causing her to target Scott instead.

After which, in the following two days, Kryssie nominated Scott and Morgan for eviction, with Scott as her intended target. However, The next day, Kryssie's plans were put in jeopardy once again as it was revealed that America's Nominee was Neeley, a close ally of Kryssie. After the announcement, the HouseGuests entered the backyard one by one for the next Power of Veto competition, where Kryssie, Scott, Morgan, Neeley, Justin and Shelby participated.

• Power of Veto ("Wall of Shame"): One by one, the HouseGuests entered the backyard, and were faced with a horizontal rock wall, with the pictures of the first three evicted HouseGuests, Cornbread, Monte and Shane, above it. They had to climb the wall to open up the pictures, which would reveal a question about that HouseGuest. They then had to return to the start and had to pick up numbered cards which answered the questions and return to that part of the wall to place the answers down. After placing all three, they had to press the buzzer at the start, and if correct, would lock in their timing. If wrong, they would need to correct the answer before buzzing in again. Should the HouseGuests fall off the wall, they would incur a three-minute time penalty. Ultimately, they had to complete the tasks within 30 minutes (not inclusive of time penalties) or they would be disqualified from the competition. Coming in just a mere 16 seconds before Scott, Morgan won the Power of Veto.

Subsequently, on Day 27, Morgan used the Power of Veto on herself, and Kryssie as Head of Household, chose Whitney as the 3rd person sitting on the couch come eviction day, along with Scott and Neeley. The next day at the live eviction, the votes landed 4-3-0, with America casting the deciding vote for the second time, this time against Neeley, making Neeley the fourth person evicted from the Big Brother House.

After Neeley's eviction, the HouseGuests proceeded to the memory wall to start the preparation for the next HoH competition, which Kryssie, as outgoing Head of Household, did not compete in.

• Head of Household ("One Strike, You're Out"): The HouseGuests were given 10 minutes to memorize several images from their stay in the Big Brother house. After which, they headed to a backyard, for a series of True/False questions based on the photos they had previously seen. If a HouseGuest makes a mistake, they are eliminated from the competition, unless everyone else had answered it wrongly. If there was still more than one HouseGuest remaining after 10 questions, they would face off in a tiebreaker. After six questions, Danielle was the last HouseGuest standing and became the fifth Head of Household of the season.

The next day, America's Care Package landed, and it was revealed that Shelby had won the power to eliminate three eviction votes that week. This shocked the Late Night Jamboree of Jason, Justin, Kryssie and Danielle, who hated her. This caused Danielle to want to put her up, in order to ensure that she is not one of the three remaining votes that week.

On Day 30 and 31, Danielle saved Jason, Justin, Kryssie, Scott, Morgan and Alex, leaving Shelby and Whitney on the block. Due to the possibility of Whitney flipping, Alex and Scott contemplated evicting her if it came down to it, as they had noticed her close relations with Justin. The next day, it was revealed that Scott was America's Nominee, after which Danielle, Scott, Shelby, Whitney, Jason and Justin competed in the next Power of Veto competition.

• Power of Veto ("The Haunting of Clementine O'Grady"): While the rest of the HouseGuests watched from the safety of the HoH room, the PoV players search a pitch-black BB house for Clementine's doll, brush and rattle. Once they located these items, each player had to place them in a toy chest located in the middle of a "blood-soaked pentagram" which marked the spot of Clementine's death. The player to complete this task in the shortest amount of time would win the PoV. Players only had 15 minutes to search before angering the spirits and ending the game. With just a small headlamp to guide the way, each player had to endure random production assistants jumping out at them at any given moment. After completing the challenge, the player joined the other HouseGuests to watch the remainder of the comp. With an astounding time of 1:22, Danielle won the Power of Veto and became the first Head of Household to also win the Power of Veto this season.

Subsequently on Day 35, after being convinced that the target of the Ballsmashers was Whitney when her target was Scott, Danielle decided to use the Power of Veto to save Whitney, and nominated Morgan in her place as a pawn. The next day during the Live Eviction, Shelby cancelled out the votes of Jason, Justin and Kryssie with her Care Package, leaving three votes to evict from America, Alex and Whitney. Ultimately, Scott was evicted over Morgan and Shelby by a unanimous vote of 3-0-0.

Shortly after Scott was evicted from the Big Brother house, the HouseGuests were informed that the next Head of Household competition would begin, and that they would challenge one at a time. As such, they proceeded to the London Room to wait for their turn.

• Head of Household ("Big Brother Over the Top Freshman Class"): The HGs were to go one by one, in which the order was by random draw, to the backyard, where they were faced with several face morphs of themselves and other HouseGuests. They had to match each face to the two people who were morphed into the picture in the fastest time possible without any hints to correct them if they were wrong. If they cannot complete within half an hour or before the previous fastest HouseGuest, they would be immediately disqualified from the competition. After racing through the competition with a time of 3:42, Shelby won the Head of Household competition.

On Day 37, America's Care Package was delivered to Jason, who won co-HoH. This granted him the rights and responsibilities of the Head of Household, and meant that Jason and Shelby would each nominate one HouseGuest for eviction. Due to the format of Safety Ceremonies, the nominations would be based on a series of alternately saving HouseGuests, with the two remaining HGs at the end becoming the nominees for the week.

The next day, Shelby saved Morgan and Jason saved Kryssie. Following which, Shelby saved Alex, and Jason saved Justin, leaving Danielle and Whitney on the block. On Day 41, Alex was revealed as America's Nominee. Shelby, as the first Head of Household for the week, drew names to reveal who would participate in the Power of Veto competition. This week Alex, Danielle, Jason, Morgan, Shelby, and Whitney competed in this week's competition.

• Power of Veto ("Balancing of Power"): In this competition, HouseGuests had to walk across a balance beam while holding a clear tube containing two balls. Once they got to the small platform at the end, they had to deposit both balls into another clear tube marked 1, 2, and 3. They then must make their way back across the balance beam and onto the original platform. If a HouseGuest fell off their balance beam, or dropped either of the balls out of the end of the tube, they would have to start over with whichever tube they were working on. If a HouseGuest got to their platform with a full tube, it would be automatically locked and they would begin the next one. Finishing first, Jason won the Power of Veto.

On the night before the Veto ceremony, Danielle and Jason decided to strike a final five deal with the Ballsmashers alliance with the promise to backdoor Justin. However, Danielle and Jason were not genuine with this deal and only made it to blindside them. On Day 42, Jason used the Power of Veto on Danielle, and he chose Morgan as the replacement nominee. On Day 43, Alex was evicted from the Big Brother house by a unanimous vote of 4-0-0.

Rachel Reilly from Big Brother 12 and Big Brother 13 entered the house shortly afterwards to host the upcoming HoH competition.

• Head of Household ("Big Brother Shopping Network"): In this competition, the HouseGuests were shown a series of infomercials featuring items relating to previous Big Brother competitions up for sale, plus shipping and handling. Afterwards, they would be quizzed in a series of true/false questions; correct answers would earn a point. The HouseGuest with the most points after seven questions would win. In the tie-breaker question, Danielle beat out Kryssie, Morgan, and Whitney for her second HoH title.

After the HoH competition, the remaining Ballsmasher alliance, Morgan and Shelby, were distraught at the thought of being alone with the remaining Late Night Jamboree. However, Morgan would go on to win the next America's Care Package and was subsequently awarded the Double Eviction Veto, which prevented her from being nominated in the initial safety ceremony and allowing her to veto one of Danielle's nomination.

After the Care Package reveal, it was the Late Night Jamboree's turn to become distraught, having realized they have no choice but to take out one of their own. After deliberating with Shelby, Morgan, and Jason, Danielle nominated Justin and Whitney with the original intent to take out Justin but changed her mind and decided to target Whitney, for fear of her flipping back to the Ballsmashers.

In the Veto ceremony, Morgan did not use the Power of Veto and Whitney was evicted in a 3-2 vote with Danielle breaking the tie.

After Whitney's eviction, the HGs drew numbers to decide the order in which they would play the next HoH competition.

• Head of Household ("It's Time to Reflect"): In this competition, houseguests had to place four mirrors on stands and adjust them to direct a laser light into a target. The HouseGuest with the fastest time wins. After experiencing a few technical difficulties with one of the mirrors, Shelby was granted a redo challenge against the player with the lowest time, Jason, and solve a new laser puzzle. With a time of 4:03 compared to Jason's time of 9:52, Shelby became the new HoH.

Despite Danielle and Jason attempting to make deals with Shelby and Morgan to target Justin, Shelby and Morgan ultimately decided that they were untrustworthy after the fake final five deal they made last week with them and Alex. Shelby and Morgan decided to strike a final four deal with Kryssie and Justin to take out Danielle. On Day 47, Shelby nominated Danielle and Jason.

On Day 48, Morgan was nominated by America.

• Power of Veto ("Domi-knows"): In this competition, the HouseGuests had to stack dominoes through a series of gates with questions about previous events and competitions. Each gate had one correct answer and one incorrect answer. The player who stacked their dominoes, successfully knocked them over and through the correct answers in the fastest time would win the Power of Veto. If they were to stack their dominoes through the wrong gate, they would incur a three-minute penalty. Once again, with the fastest time of 9:38, Shelby won the PoV.

Subsequently on Day 49, Shelby used the Power of Veto to save Morgan leaving Danielle and Jason up on the block. The next day during the Live Eviction, Danielle was evicted over Jason by a unanimous vote of 4-0.

After Danielle's eviction, HouseGuests competed in a mental and endurance Head of Household competition.

• Head of Household ("Keep You Posted"): In this competition, HouseGuests had to answer questions in the quiz part of the game in which the answers were either: male or female. The answers were then revealed during the endurance portion of the game where houseguests stood on a post. If they answered correctly, they stayed where they were. If they answered incorrectly, they moved to a smaller post in front of them. If a HouseGuest had not reached their final post after all the questions have been read, they were told to move forward every 5 minutes until they reached the smallest post. Morgan ended up lasting longer than Jason, Justin, and Kryssie.

• Power of Veto ("Maize-maze"): In this competition, the HouseGuests had to make their way through a maze collecting three heirs of corn. Once they had all three heirs of corn, they needed to find the exit and press a button to lock in their time. Finishing with a time of 1:30, Jason won the final Power of Veto.

Subsequently on Day 56, Jason removed himself from the block, and being the only possible replacement nominee, Shelby took his place. The next day during the Live Eviction, Jason and Justin voted to evict Shelby.

After Shelby's eviction, the four HouseGuests went out to the backyard to compete in their final Head of Household competition.

• Head of Household ("Uphill Battle"): In this competition, HouseGuests had to maneuver color coded balls up a board into the correct pockets using two ropes strapped to a metal bar. They must avoid pitfall holes throughout the board so that their ball does not fall through. Jason finished filling all of his pockets correctly first to ensure his safety into the Final 3.

On Day 60, Jason decided to take Kryssie with him to the Final 3. In doing so, Justin and Morgan must participate in a Do or Die competition to see who earns the final spot in the Final 3.

• Do or Die Competition: In this competition, Justin and Moragn must match pictures of evicted HouseGuests to nine different questions correctly in order to solve the puzzle. At the sound of a buzzer, they had to study clues to each picture, race through a set of metal bars, jump over hay bales, and look through the different pictures. Once they got a picture, they would return through the obstacles, to the puzzle board, and place the picture above the clue that they think is a match. Only one photo can be carried through the obstacles at a time. Some clues may pertain to more than one HouseGuest.

Morgan rang in first with the correctly finished puzzle earning the final spot in the Final 3, sending Justin out the door.